Annotation of rpl/lapack/lapack/zgemlq.f, revision 1.1
1.1 ! bertrand 1: *
! 2: * Definition:
! 3: * ===========
! 4: *
! 5: * SUBROUTINE ZGEMLQ( SIDE, TRANS, M, N, K, A, LDA, T,
! 6: * $ TSIZE, C, LDC, WORK, LWORK, INFO )
! 7: *
! 8: *
! 9: * .. Scalar Arguments ..
! 10: * CHARACTER SIDE, TRANS
! 11: * INTEGER INFO, LDA, M, N, K, LDT, TSIZE, LWORK, LDC
! 12: * ..
! 13: * .. Array Arguments ..
! 14: * COMPLEX*16 A( LDA, * ), T( * ), C(LDC, * ), WORK( * )
! 15: *> \par Purpose:
! 16: * =============
! 17: *>
! 18: *> \verbatim
! 19: *>
! 20: *> ZGEMLQ overwrites the general real M-by-N matrix C with
! 21: *>
! 22: *> SIDE = 'L' SIDE = 'R'
! 23: *> TRANS = 'N': Q * C C * Q
! 24: *> TRANS = 'C': Q**H * C C * Q**H
! 25: *> where Q is a complex unitary matrix defined as the product
! 26: *> of blocked elementary reflectors computed by short wide
! 27: *> LQ factorization (ZGELQ)
! 28: *>
! 29: *> \endverbatim
! 30: *
! 31: * Arguments:
! 32: * ==========
! 33: *
! 34: *> \param[in] SIDE
! 35: *> \verbatim
! 36: *> SIDE is CHARACTER*1
! 37: *> = 'L': apply Q or Q**T from the Left;
! 38: *> = 'R': apply Q or Q**T from the Right.
! 39: *> \endverbatim
! 40: *>
! 41: *> \param[in] TRANS
! 42: *> \verbatim
! 43: *> TRANS is CHARACTER*1
! 44: *> = 'N': No transpose, apply Q;
! 45: *> = 'T': Transpose, apply Q**T.
! 46: *> \endverbatim
! 47: *>
! 48: *> \param[in] M
! 49: *> \verbatim
! 50: *> M is INTEGER
! 51: *> The number of rows of the matrix A. M >=0.
! 52: *> \endverbatim
! 53: *>
! 54: *> \param[in] N
! 55: *> \verbatim
! 56: *> N is INTEGER
! 57: *> The number of columns of the matrix C. N >= 0.
! 58: *> \endverbatim
! 59: *>
! 60: *> \param[in] K
! 61: *> \verbatim
! 62: *> K is INTEGER
! 63: *> The number of elementary reflectors whose product defines
! 64: *> the matrix Q.
! 65: *> If SIDE = 'L', M >= K >= 0;
! 66: *> if SIDE = 'R', N >= K >= 0.
! 67: *>
! 68: *> \endverbatim
! 69: *>
! 70: *> \param[in] A
! 71: *> \verbatim
! 72: *> A is COMPLEX*16 array, dimension
! 73: *> (LDA,M) if SIDE = 'L',
! 74: *> (LDA,N) if SIDE = 'R'
! 75: *> Part of the data structure to represent Q as returned by ZGELQ.
! 76: *> \endverbatim
! 77: *>
! 78: *> \param[in] LDA
! 79: *> \verbatim
! 80: *> LDA is INTEGER
! 81: *> The leading dimension of the array A. LDA >= max(1,K).
! 82: *> \endverbatim
! 83: *>
! 84: *> \param[in] T
! 85: *> \verbatim
! 86: *> T is COMPLEX*16 array, dimension (MAX(5,TSIZE)).
! 87: *> Part of the data structure to represent Q as returned by ZGELQ.
! 88: *> \endverbatim
! 89: *>
! 90: *> \param[in] TSIZE
! 91: *> \verbatim
! 92: *> TSIZE is INTEGER
! 93: *> The dimension of the array T. TSIZE >= 5.
! 94: *> \endverbatim
! 95: *>
! 96: *> \param[in,out] C
! 97: *> \verbatim
! 98: *> C is COMPLEX*16 array, dimension (LDC,N)
! 99: *> On entry, the M-by-N matrix C.
! 100: *> On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.
! 101: *> \endverbatim
! 102: *>
! 103: *> \param[in] LDC
! 104: *> \verbatim
! 105: *> LDC is INTEGER
! 106: *> The leading dimension of the array C. LDC >= max(1,M).
! 107: *> \endverbatim
! 108: *>
! 109: *> \param[out] WORK
! 110: *> \verbatim
! 111: *> (workspace) COMPLEX*16 array, dimension (MAX(1,LWORK))
! 112: *> \endverbatim
! 113: *>
! 114: *> \param[in] LWORK
! 115: *> \verbatim
! 116: *> LWORK is INTEGER
! 117: *> The dimension of the array WORK.
! 118: *> If LWORK = -1, then a workspace query is assumed. The routine
! 119: *> only calculates the size of the WORK array, returns this
! 120: *> value as WORK(1), and no error message related to WORK
! 121: *> is issued by XERBLA.
! 122: *> \endverbatim
! 123: *>
! 124: *> \param[out] INFO
! 125: *> \verbatim
! 126: *> INFO is INTEGER
! 127: *> = 0: successful exit
! 128: *> < 0: if INFO = -i, the i-th argument had an illegal value
! 129: *> \endverbatim
! 130: *
! 131: * Authors:
! 132: * ========
! 133: *
! 134: *> \author Univ. of Tennessee
! 135: *> \author Univ. of California Berkeley
! 136: *> \author Univ. of Colorado Denver
! 137: *> \author NAG Ltd.
! 138: *
! 139: *> \par Further Details
! 140: * ====================
! 141: *>
! 142: *> \verbatim
! 143: *>
! 144: *> These details are particular for this LAPACK implementation. Users should not
! 145: *> take them for granted. These details may change in the future, and are unlikely not
! 146: *> true for another LAPACK implementation. These details are relevant if one wants
! 147: *> to try to understand the code. They are not part of the interface.
! 148: *>
! 149: *> In this version,
! 150: *>
! 151: *> T(2): row block size (MB)
! 152: *> T(3): column block size (NB)
! 153: *> T(6:TSIZE): data structure needed for Q, computed by
! 154: *> ZLASWLQ or ZGELQT
! 155: *>
! 156: *> Depending on the matrix dimensions M and N, and row and column
! 157: *> block sizes MB and NB returned by ILAENV, ZGELQ will use either
! 158: *> ZLASWLQ (if the matrix is wide-and-short) or ZGELQT to compute
! 159: *> the LQ factorization.
! 160: *> This version of ZGEMLQ will use either ZLAMSWLQ or ZGEMLQT to
! 161: *> multiply matrix Q by another matrix.
! 162: *> Further Details in ZLAMSWLQ or ZGEMLQT.
! 163: *> \endverbatim
! 164: *>
! 165: * =====================================================================
! 166: SUBROUTINE ZGEMLQ( SIDE, TRANS, M, N, K, A, LDA, T, TSIZE,
! 167: $ C, LDC, WORK, LWORK, INFO )
! 168: *
! 169: * -- LAPACK computational routine (version 3.7.0) --
! 170: * -- LAPACK is a software package provided by Univ. of Tennessee, --
! 171: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
! 172: * December 2016
! 173: *
! 174: * .. Scalar Arguments ..
! 175: CHARACTER SIDE, TRANS
! 176: INTEGER INFO, LDA, M, N, K, TSIZE, LWORK, LDC
! 177: * ..
! 178: * .. Array Arguments ..
! 179: COMPLEX*16 A( LDA, * ), T( * ), C( LDC, * ), WORK( * )
! 180: * ..
! 181: *
! 182: * =====================================================================
! 183: *
! 184: * ..
! 185: * .. Local Scalars ..
! 186: LOGICAL LEFT, RIGHT, TRAN, NOTRAN, LQUERY
! 187: INTEGER MB, NB, LW, NBLCKS, MN
! 188: * ..
! 189: * .. External Functions ..
! 190: LOGICAL LSAME
! 191: EXTERNAL LSAME
! 192: * ..
! 193: * .. External Subroutines ..
! 194: EXTERNAL ZLAMSWLQ, ZGEMLQT, XERBLA
! 195: * ..
! 196: * .. Intrinsic Functions ..
! 197: INTRINSIC INT, MAX, MIN, MOD
! 198: * ..
! 199: * .. Executable Statements ..
! 200: *
! 201: * Test the input arguments
! 202: *
! 203: LQUERY = LWORK.EQ.-1
! 204: NOTRAN = LSAME( TRANS, 'N' )
! 205: TRAN = LSAME( TRANS, 'C' )
! 206: LEFT = LSAME( SIDE, 'L' )
! 207: RIGHT = LSAME( SIDE, 'R' )
! 208: *
! 209: MB = INT( T( 2 ) )
! 210: NB = INT( T( 3 ) )
! 211: IF( LEFT ) THEN
! 212: LW = N * MB
! 213: MN = M
! 214: ELSE
! 215: LW = M * MB
! 216: MN = N
! 217: END IF
! 218: *
! 219: IF( ( NB.GT.K ) .AND. ( MN.GT.K ) ) THEN
! 220: IF( MOD( MN - K, NB - K ) .EQ. 0 ) THEN
! 221: NBLCKS = ( MN - K ) / ( NB - K )
! 222: ELSE
! 223: NBLCKS = ( MN - K ) / ( NB - K ) + 1
! 224: END IF
! 225: ELSE
! 226: NBLCKS = 1
! 227: END IF
! 228: *
! 229: INFO = 0
! 230: IF( .NOT.LEFT .AND. .NOT.RIGHT ) THEN
! 231: INFO = -1
! 232: ELSE IF( .NOT.TRAN .AND. .NOT.NOTRAN ) THEN
! 233: INFO = -2
! 234: ELSE IF( M.LT.0 ) THEN
! 235: INFO = -3
! 236: ELSE IF( N.LT.0 ) THEN
! 237: INFO = -4
! 238: ELSE IF( K.LT.0 .OR. K.GT.MN ) THEN
! 239: INFO = -5
! 240: ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
! 241: INFO = -7
! 242: ELSE IF( TSIZE.LT.5 ) THEN
! 243: INFO = -9
! 244: ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
! 245: INFO = -11
! 246: ELSE IF( ( LWORK.LT.MAX( 1, LW ) ) .AND. ( .NOT.LQUERY ) ) THEN
! 247: INFO = -13
! 248: END IF
! 249: *
! 250: IF( INFO.EQ.0 ) THEN
! 251: WORK( 1 ) = LW
! 252: END IF
! 253: *
! 254: IF( INFO.NE.0 ) THEN
! 255: CALL XERBLA( 'ZGEMLQ', -INFO )
! 256: RETURN
! 257: ELSE IF( LQUERY ) THEN
! 258: RETURN
! 259: END IF
! 260: *
! 261: * Quick return if possible
! 262: *
! 263: IF( MIN( M, N, K ).EQ.0 ) THEN
! 264: RETURN
! 265: END IF
! 266: *
! 267: IF( ( LEFT .AND. M.LE.K ) .OR. ( RIGHT .AND. N.LE.K )
! 268: $ .OR. ( NB.LE.K ) .OR. ( NB.GE.MAX( M, N, K ) ) ) THEN
! 269: CALL ZGEMLQT( SIDE, TRANS, M, N, K, MB, A, LDA,
! 270: $ T( 6 ), MB, C, LDC, WORK, INFO )
! 271: ELSE
! 272: CALL ZLAMSWLQ( SIDE, TRANS, M, N, K, MB, NB, A, LDA, T( 6 ),
! 273: $ MB, C, LDC, WORK, LWORK, INFO )
! 274: END IF
! 275: *
! 276: WORK( 1 ) = LW
! 277: *
! 278: RETURN
! 279: *
! 280: * End of ZGEMLQ
! 281: *
! 282: END
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